Much of the daily heat for greenhouses will come from the sun, but if you want your greenhouse to be more than a few degrees above the outside temperature at night, you will need to provide it with a heat source. The most popular greenhose heating systems are be fueled by electricity, propane, or natural gas. The choice of a greenhouse heating system and fuel depends on what is locally available, the heating requirements of the plants, cost, and individual choice. Heating requirements for your greenhouse can be determined with our Greenhouse Heater Size Calculator. Choose from our assortment of top quality electric and gas heating options below.